The invention relates to seals. More particularly, the invention relates to sealing between concentric members.
Sealing between inboard and outboard concentric members has presented practical problems, especially when involving aggressive or high temperature fluids. The problems generally relate to the capturing of the seal by one of the members. For example, the seal may be captured in a radially open channel/groove in one of the members and may engage a cylindrical surface of the other member. If the channel is an outwardly open channel in the inner/inboard member, placing the seal in the channel presents difficulties. An elastomeric seal may simply be stretched and released into the channel. A metallic seal may need to be split to permit its expansion. Accordingly, side-by-side dual split metallic seals are often used in combinations where the splits are offset from each other and the associated gaps are sealed radially by means of another split ring between the pair and the channel base.
Whereas elastomeric seals may suffer lower robustness than metallic seals, the metallic seals may suffer greater complexity and manufacturing cost. An alternative may involve assembling at least one of the members of multiple pieces so that the channel is closed only after a continuous metallic seal ring is installed. This, however, also presents manufacturing and space-efficiency detriments.
An inwardly open channel in the outer/outboard member may be used with an elastomeric or split seal wherein the seal is contracted (e.g., by looping, flexing, or overlapping of ends) to permit installation and then manipulated (e.g., worked in by hand) to fill the channel. This presents similar detriments to those described above.